(i) Field of the Invention
The present invention relates to a device which can be used in surgery, and more particularly to a device for pinpointing small suspect lesions of the breast, such as micro-calcifications, with a view to their optimized ablation by surgical means, as well as to an apparatus for positioning it.
(ii) Description of Related Art
Screening for breast cancers is normally done by mammography, since this technique permits detection of lesions of small dimensions, such as micro-calcifications. It is then necessary to remove tissues from the mammary gland in order to analyze them and verify their possible cancerous nature. This removal is generally done by surgical means, or by biopsy, or else by needle puncture.
The practitioner (surgeon) normally pinpoints the suspect lesions on mammography images by taking the nipple of the breast as a reference point, and uses the frontal and profile measurements in order to determine approximately the position of the lesion from which a sample is to be taken.
One of the main difficulties encountered by practitioners is that of locating the lesion which has been detected by mammography. This is because the position of the breast is very different during mammography (frontal and profile), where the patient is in a seated position, the breast pressed between two plates, and during the operating phase where the patient is generally lying on her back on an operating table.
The result of this is that the mammography reference markers do not correspond precisely to the actual position of the lesion during the removal operation, regardless of whether this is done by surgery, by biopsy or by puncture. Now, the lesions consisting of micro-calcifications are often incipient and noninvasive cancers of small dimensions, the diameter of which is of the order of magnitude of millimeters and does not exceed 1 cm. These lesions do not present any particular consistency or coloration. Pinpointing them is therefore difficult, even after mammography from several angles, for example frontal and profile.
In practice, the surgeon is forced to make an estimate and remove a relatively large volume of breast tissue susceptible of containing the suspect lesion. The sample removed is then checked by X-ray to verify the presence of the micro-calcifications, and then analyzed on the spot by a specialist (anatomical pathologist).
Despite all the precautions taken during these operations, it is very often discovered, subsequently, that there are micro-calcifications still remaining in the breast. These micro-calcifications are detected during mammographs performed several weeks after the operation described hereinabove. It is then often necessary to perform another operation.
Because of these difficulties, and in order to avoid having to perform several operations in succession, the surgeon is compelled to remove much greater quantities of tissue than would be necessary if the lesions detected by mammography could thereafter be pinpointed with good reliability and satisfactory precision. Moreover, the surgeon cannot be certain that all the micro-calcifications have been removed other than by broadening the ablation of tissues excessively, which can additionally have a considerably adverse esthetic and psychological impact on the patient.
Various devices have been proposed in an attempt to overcome these difficulties. For example, patent FR-A-2,660,545 describes biopsy equipment in association with mammography from two angles with the aid of a rotating head taking the images, this equipment being intended to locate suspect lesions corresponding to incipient cancers. However, this equipment is complex and its use is not very convenient for the patient.
Patent FR-A-2,666,217 describes a device for stereotaxic pinpointing and puncturing of a lesion of small dimensions, detected by mammography, by means of a trocar or needle for aspiration biopsy. This device is designed to permit two X-ray images to be taken from two different angles, the patient's breast being pressed between two plates, one of which includes a zone for access to the breast, as well as a support for vertical guidance of a puncture needle, the movement of which is determined as a function of the results of the detection of the lesion using the mammography images. This device necessitates immobilizing the patient's breast between the two plates, not only during the mammography, but also during the operation of puncturing and analysis of the removed sample, that is to say for a prolonged period of time, which is not conducive to the patient's comfort.
Patent U.S. Pat. No. 5,158,084 describes a device for pinpointing lesions in a tissue, comprising a flexible radiopaque wire having at least two markers which are detectable by palpation and which are intended to allow the surgeon to determine the position of the end of the wire without needing to trace it in its entirety.
Patent U.S. Pat. No. 4,592,356 describes an anchoring device for biopsy, comprising a needle whose point is in the form of a double hook and whose rod includes threading for the positioning of a blocking piece against the surface of the skin.
Patent application WO-A-90/15576 describes an apparatus for positioning a pinpointing device, comprising an anchoring means of helical shape fixed on a rod which is capable of being set in rotation inside a hollow needle for the purpose of inserting the anchoring means in the tissues.